Pedicle screws are often used for spinal procedures such as when doing spine arthrodesis—to fuse several vertebrae into one rigid body—or when straightening out a pathologically bent spine. The insertion of pedicle screws is a procedure that requires delicate precision. That is, pedicle screw placement should be carried out precisely in target bone and the first step to success is good planning. A well-structured and precise surgical plan can contribute to a successful surgery in several ways, such as: saving time during surgery, which in turn reduces the risk of infection and allowing shorter operation time and reduce any subsequent operation which can decrease costs. Done properly, planning can also provide information to surgeons so that viable approaches are identified before they are physically tried. This reduces the number of preventable mistakes, had the surgeons had more information of the situation. Also, planning can give information about which tools and implants are needed and exact lengths and diameters for screws can be determined in advance.
In the past, manual insertion has been used, where the screws are completely adjusted by a surgeon/user to fit the pedicles. This is a very time consuming approach. Manually planning the placement of every single pedicle screw in 3D can be very tedious, particularly where multiple screws are to be inserted. In the past, model based insertion has also been used where the vertebra needs to be segmented and matched to a model of a standard vertebra of that type. However, this model-based planning requires a segmentation step, which can be a relatively lengthy action and may not be suitable accurate or succeed if the image is of bad quality.
Despite the above, there remains a need for automated planning methods and systems which can reliably provide planning information for proper pedicle screw placement in the spine of individual patients.